Case Report: Equine allogeneic umbilical cord blood mesenchymal stromal cells (CB-MSC) as adjunctive therapy in a foal with septic arthritis and osteomyelitis.
Authors: Horna Marta, Merchán Muñoz Alejandro, Goodrich Laurie, Pezzanite Lynn, Dow Steven, Koch Thomas R, Alizadeh Amir H, Mehrpouyan Sahar, Koenig Judith
Journal: Frontiers in veterinary science
Summary
# Editorial Summary Septic arthritis and osteomyelitis in foals present a significant clinical challenge, particularly when infections prove refractory to conventional lavage and antibiotic protocols. This case report documents the treatment of an 8-day-old Thoroughbred filly with progressive multi-site infection—including septic arthritis of both tibiotarsal and elbow joints complicated by ulnar osteomyelitis and pathological fracture—using allogeneic umbilical cord blood-derived mesenchymal stromal cells (CB-MSCs) as adjunctive therapy alongside systemic and intra-articular antibiotics. The filly received three intra-articular injections of 15 million TLR3-activated CB-MSCs combined with meropenem into the affected elbow joint and fracture site, plus two systemic administrations of non-activated CB-MSCs (1 million cells/kg intravenously), alongside initial chloramphenicol therapy; this approach resulted in complete resolution of the septic process with radiographic evidence of substantial ulnar remodelling at 12-month follow-up and return to soundness. The immunomodulatory, anti-inflammatory, and potentially antimicrobial properties of CB-MSCs—particularly when activated via toll-like receptor 3 (TLR3)—may enhance bacterial clearance and tissue healing in cases where standard interventions have failed. Whilst recognising the limitations of a single case report, these findings suggest that CB-MSC therapy warrants further investigation as a potential adjunct for managing refractory intra-synovial and osseous infections in foals, particularly given the escalating concerns surrounding antibiotic resistance in equine medicine.
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Practical Takeaways
- •CB-MSCs may represent a viable adjunctive therapy option for cases of septic arthritis and osteomyelitis that fail to respond adequately to conventional treatment (lavage, antibiotics), though this remains a single case.
- •TLR3-activation of MSCs prior to intra-articular injection may enhance antimicrobial efficacy; consider this when accessing experimental cell therapy protocols for resistant infections.
- •Successful long-term outcomes (12-month soundness and bone remodeling) suggest CB-MSC therapy merits further investigation in prospective clinical trials for septic bone and joint disease in foals.
Key Findings
- •A foal with refractory septic arthritis and osteomyelitis unresponsive to needle lavage, arthroscopic lavage, and intra-articular antibiotics achieved complete resolution following treatment with TLR3-activated cord blood-derived mesenchymal stromal cells (CB-MSCs) combined with meropenem.
- •Three intra-articular treatments with 15 million TLR3-activated CB-MSCs plus two systemic IV treatments with non-activated CB-MSCs (1 million cells/kg) resulted in complete healing of septic arthritis and osteomyelitis.
- •At 12-month follow-up, the foal remained sound with significant radiographic remodeling of the ulna fracture site, suggesting durable functional recovery.